What is Causing the Increase in Autism Prevalence?

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community. We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and will address the other themes we received in this weekly post.

In the last two decades, autism prevalence as reported in the scientific literature has increased by more than 600%. In 2009, the latest estimate of autism prevalence in the United States, as reported by the Centers for Disease Control was 1 in 110 children[1]. Since then, a number of studies have sought to investigate the cause(s) of this dramatic increase in autism prevalence over time. The most recent findings suggest that at least a portion of the increase in prevalence can be attributed to changes in diagnostic practices and increased awareness of autism over time, as well as other social factors such as advanced parental age. However, converging evidence also suggests that while these factors account for a portion of the increase, they cannot alone explain the dramatic rise in autism prevalence.

The criteria for assessing autism has changed over the last 20 years resulting in a broadening of autism diagnoses and the identification of cases that would not have been diagnosed as such using older criteria. Looking at a population of children in California, researchers from Columbia University reported[2] that approximately 26% of the rise in autism caseload between 1992 and 2005 could be directly attributed to changes in diagnostic criteria, specifically the shift from mental retardation diagnoses to autism diagnoses. In other words, 1 in 4 children diagnosed with autism in California today would not have been diagnosed using older diagnostic criteria.

Another aspect of the autism landscape that has changed over the past 20 years is an increase in the awareness of autism among the general public as well as healthcare professionals. In 2010, the Columbia University research team again examined[3] the California sample in an effort to quantify the influence of autism awareness on the rise in autism prevalence. The investigators found that children living in close proximity to another child that had been previously diagnosed with autism had a better chance of being diagnosed with autism themselves. The proposed explanation is information diffusion, or parents talking to and educating other parents about autism resulting in an increased likelihood of their children being diagnosed. It is estimated that 16% of the increase in autism prevalence over time in California was due to social influence and increased awareness.

An additional social factor that has been implicated in contributing to the increase in autism prevalence is advanced parental age. A number of recent publications investigating the relationship between parental age and autism have demonstrated that older parents are at increased risk for having a child with autism. This is not surprising since increased parental age is associated with a slightly increased risk for other developmental disorders as well. Researchers from the California Department of Public Health reported[4] that parental age and particularly maternal age is a significant risk factor for autism, with a 10-year increase in maternal age increasing the odds of having a child with autism by 38% and mothers over the age of 40 at highest risk. Researchers at Columbia University similarly found[5],[6] that older mothers and fathers were at increased risk of having a child with autism and estimated that the increase in parental age over time can account for 11% of the increase in prevalence over the same time period. The underlying mechanism behind the relationship between increased parental age and risk for autism is currently under investigation.

Based on the abovementioned research, approximately 53% percent of the increase in autism prevalence over time may be explained by changes in diagnosis (26%), greater awareness (16%), and an increase in parental age (11%). While this research is beginning to help us understand the increase in autism prevalence, half of the increase is still unexplainedand not due to better diagnosis, greater awareness, and social factors alone. Environmental factors, and their interactions with genetic susceptibilities, are likely contributors to increase in prevalence and are the subject of numerous research projects currently supported by Autism Speaks.

The increase in autism prevalence is real and the public health crisis is growing. More families are affected by autism today then ever before. While Autism Speaks has cast a wide net to explore the role of genetic and environmental factors in increasing the risk for autism, the research community requires additional funding support to increase the pace of discovery. Never before has the need for research into the causes of autism and effective treatments for autism been greater.

I do not drink soft drinks or chew gum, nor did I when I was a child. I was raised by very strict parents who did not permit candy. Furthermore, I have never enjoyed fast food restaurants and the typical American diet. Yet I was considered “minimally brain damaged” as a child and diagnosed as on the autism spectrum as an adult. My diet is organic and that of a vegetarian, but my immune system is dysfunctional. It is what it is. I do not think Aspartame is a factor at all, not in regards to myself, my children on the spectrum, and quite a few others.

Then again, I do believe there are multiple factors that contribute. I was born prematurely in the mid 1960s, substantial decades before the increase.

Noreen

October 25, 2010 at 9:55 pm

“Premature” is a risk factor but it also sounds like genetics play a part in your family. You sound like you have a nice healthy lifestyle going and are very HF. All good points!

If you have a child on the spectrum and you plan to have another baby PLEASE check out http://www.earlistudy.org/ to see if you’re eligible. This is one of the studies funded by Autism Speaks and NIH to explore genetic/environmental interaction. Check out the “Early Autism Risk Longitudinal Investigation” facebook page, too! I and several others working on this study have children on the autism spectrum, and we’re looking for answers.

my daughter regession autism and Developmental delay at 19 months while I was pregnant with my second child. My son has autism with DD and dx at 14 months because I already knew what To look out for. My two kids have are on two different scales of autism. Same parents. We have done massive gentic testing negative. I want to have a third child my husband said he can’t handle a third child with autism. I am the only family member to have children with this. At a family reunion of 1000 we did asked everyone. We did find out that 4 members of had speech delay and 3 had learning problems.

Noreen

October 25, 2010 at 10:00 pm

I think that Autism is HIGHLY related to ADHD or ADD? This is something that people display but they can get away with not getting a diagnosis (my son has ADHD and is highly intelligent). I am sorry both of your kids were diagnosed. It does sound like a handful and can also understand/respect your husbands feelings as well. It is exhausting but worth it. Speech delays are related and many people are undiagnosed. My husband had Speech, OT and PT while in 1st grade. Can you say HF Autism :o) He’s doing well.

Dianna

October 29, 2010 at 9:29 am

agreed Noreen—there are many similarities between ADHD and autism/Aspergers. The similarities increase if the child is also gifted (sounds like yours might be). My sone has ADHD, is gifted, and has a mild learning disability–he was assessed for Aspergers b/c of social difficulties that did not really start until 2nd grade. I have been in the field for 19 years and here is the difference between ADHD and autism/ Aspergers. ADHD kids have difficulty with social issues due to lack of attention and impulsive behavior. Gifted kids also tend to be socially delayed due to not being able to connect with kids their own age due to increased intellegence. However, both gifted and ADHD kids identify and know different emotions, display empathy and theroy of mind…they also have correct intonation for the situation (disaster vs. party). They understand jokes and sarcasm…
these are just a few differences. There are some studies going on in the functional neurology area that are showing that ADHD and autism are more alike than different. They do share many characteristics, but are not the same. My issues with my son might be heartbreaking at times…but in comparison to what the families that I serve deal with it is very mild as I know my son will go to college, live on his own, and find, eventually, his nitch.

In a forum to discuss science issues can I ask “applied behavior analysis” is the only proven science which is effective in the treatment of autism why are treatments which have no scientific proof or grounding receiving the same support from autism speaks ?
Perhaps I am missing something?

I must say besides ABA there were a few things that really did work for my ASD child. Learning/Visual DVD’s (he learned how to tell time with this), music definitely helped my child to “use his voice and use words”, Diet He did well on both the SCD and GFCF diets with SIGNIFICANT improvements mostly in stims and behavior, OT – gave my son his first words and expanded on it also strengthened his muscles (big believer in OT for these kids because of Sensory)

What are statistics now showing the ratio of children with Down syndrome being positively diagnosed with a form of ASD? Our daughter is 10 and was diagnosed 7 years ago. What is being done to promote getting children with Down syndrome diagnosed with ASD?

I think it is time to accept that environmental factors play the most important role in the increase of autism!!!!! Intolerance in children to the CRAP that is put in our foods such as pesticides, hormones, additives, dyes, synthetic sweeteners and artificial ingredients is probably one of the main causes. Until the medical community accepts this fact… and informs parents appropriately of the true and possible consequences from vaccinating (Vaccines still contain mercury and other preservatives that are never safe to give to any human!!) infants with the schedule currently suggested, WE WILL NOT see a decrease!!!!!!!!!!!!! This article was completely useless. A parent dealing with an autistic child, I guarantee you, could care less about the reasons given. Focus on finding the true cause!!

Karla – As a parent of a child with autism, I have heard every imaginable cause for why my son is autistic, ranging from the food that he eats, to vaccines to the fact that he had a bad infection when he was born. While I am always open to finding out more, I wonder if you are able to provide any facts to justify your claim that it was caused by things such as pesticides. The spike in autism may correlate to thing such as this (I’m not an expert), but can you explain how the rise has been so dramatic, considering that many of these things were around in some form well before the observed spike? I tend to believe that a large part of any genetic disorder finding more prevalence tends to be the age of the mother…..doctors have believed this for years, as they have always considered women in their late 30s/40s to be at a higher risk, and have done much more screening than for younger mothers.

Again, as great as my son is, no parent would wish for their child to be different. I have two passions for him….first, I want to ensure that more understanding/acceptance is available in the community for my son when he reaches adulthood (at one point, diabetes and epilepsy were looked upon differently than they are now). The 2nd thing is that we discover more about its causes. No one is dismissing what you say, Karla, but for proponents of your theories to become more credible, some facts would be welcome (and not biased opinions)

Larry

Noreen

October 25, 2010 at 10:12 pm

Larry – I to agree with Karla. It is very apparent that even the medical community is very “touchy” about the subject (because they’ve all experienced Vaccine Reactions at times). I was told by a Dr. not to sign the Hep B consent form (by a Dr. because of what they’ve seen/suspected). I regret to this day getting a FLU shot that was recommended while I was pregnant. So far, my only child that has AUTISM was the one that received this shot while I was pregnant with him. DRUGS are definitely “suspect” and sometimes Maternal Instinct does count for something. You’re not a woman or a Mother, so you wouldn’t understand BUT obviously, with ALL the numbers, NO ONE is going to ADMIT anything. Immune dsyfunction is Very Common in 20-40% of these kids and always has been. What, pray tell, effects Immunity between 0-3 years. You tell me now that Corps have upped the shots from 6-33!!!?

Greg

November 29, 2010 at 1:53 am

Currently experts tout the increase in Autism to be at 600% from 1978. That is an alarming number that cannot be explained by changes in diagnostic criteria & parents of late age. These two items account for a 25% increase in the number of Autism cases. I strongly believe that nutrition and what we ingest has a correlation to the rise in Autism in the US. Pesticides and food additives may be the culprit. Especially those that can accumulate in the body. Some artificial sweeteners and pesticides have shown to case nerve damage for an extended time and occasionally some people have life long battles from extended exposure to these chemicals. While testing for these items are only for a short time 3 – 5 years. Longer tests say 10 – 15 years may uncover nerve damage that may be attributed to the rise in Autism. Please remember it is not just what we feed our children from birth forward. More importantly it is what our parents consume and what we have consumed throughout our lifetime. The damage to our DNA (nerve mapping specifically) from food sources eventually manifest in our children in the “disease” coined Autism. The increase can be easily be attributed to the changes in how much processed we consume and the pesticides & fertilizers already present in the soil in the US and South America where the majority of our food is grown.

I too believe we as a society are poisoning ourselves. Preservatives, dyes, artificial sweetners etc. I also believe are one of the main causes but not just of autism but of other diseases plaging our society…diabetes, gluten intolerance reumatory arthritis, breathing issues (more children are on inhalers and breathing med’s than you can count)and allergies to name a few. But food and medicine is big business and we as a society on the whole move to fast to slow down and cook,home bake and even exercise…..its fast food, frozen food ,bread, chips and soda to wash it down. We unfortunatly are killing ourselves.

I appreciate that Autism Speaks is so evidence-based in its positions. Comments by readers on things like aspartame being a cause are not supported by any research, and such conjecture is purely anecdotal. As the father of a 10 year old with very significant autism, no one is more anxious to find a way to prevent this condition going forward. However – Speculation, without compelling evidence, can lead to rabbit trails in the pursuit of the root cause of autism.

How about LONG TERM studies of Vaccines. You might want to read up on the history of the DPT shot Einstein!!! Most times LOBBY is done for Dirty, Dirty reasons…but it’s OK, it will effect majority of our sons/boys, no big deal???

Amen Jack! And Noreen, vaccines have been being studied since before my time. I worked with the 2nd President of the ASA and her son. DPT was considered a possible cause when her son was small—study after study has been done. I also work with a family who has 3 boys with autism –1st 2 have allergy to contents of shots therefore the 3rd was never given one shot…his autism is more severe than his 2 older brothers. And all 3 are non-verbal classic cases of autism (no question or chances that diagnosis is wrong).

Has the percentage increase for other syndrome, such as Down’s syndrome, gone up at a similar percentage to that of Autism? We have always heard that the chances of a baby being born with Down’s increases with the age of the parents, so I am wondering if the level for this disorder has seen similar growth to Autism with the average age of parents getting older.

What I find more interesting is that the age of the parents, particularly, the age of the mother, is potentially one of the reasons for the increased prevalance of autism. I am waiting to hear about the research on that one. I am an older mother. I had my son (who is typically developing) at age 34.5, and I had my daughter (who is diagnosed with ASD) at nearly 37 years old.

Age has been proven to be a Risk factor. Also, second child has a higher incident of being on the Spectrum. Being born between Oct. & March, when ear infections and virals seem to be at high spread, seem to give a higher risk (had more infections/antibiotics prescribed), obviously if you have Autism or severe ADHD in your family a much higher risk, anyone who has received Speech, OT or PT at a young age with low muscle tone (possible undx’d HF), you have a higher risk. The thing that gets me is that people describe Autism in so many different ways (neurological, developmental, behavioral, disease?, social disorder, etc.) no one really seems to know what is going on. Liver functioning at birth or Jaundice could also now be a risk factor. Risk factors help in possibly lowering (say age, having babies at a typical physically fit age 18-35) and people realizing that YES there is a BIOLOGICAL CLOCK AFTER ALL and guess what THAT INCLUDES YOU TOO MEN. :)

A 600% increase in any disease over the course of such a short time means environmental factors are playing a primary role in the rise of the disability/ disease. Right now AS, the NIH still spend $10 on brain/gene research for every $1 they spend on environmental research.

The numbers are getting worse not better. We need to stop talking about environmental research and start actually investing in it in a serious manner.

Jack, my 9 yr old has severe autism and he went from a typical talking toddler to a screaming, miserable, febrile seizure prone baby who failed to recognize his own family within months after a catch up vaccination series. This isn’t conjecture- this is a human being’s life. If this isn’t your experience I am glad for your son.

Katie – I totally agree. My son started “seizures/freak outs” after the 3rd DPT and a whole bunch of other shots they added. I feel he sufferred a stroke as a result! or several of them and his head ached (inflammation) I could tell as a mom and they way he held it and was screaming. His leg inflamed like a balloon after his flu shot and the inflammation stayed for months. Even his groin area inflammed and I’m sure probably lots of places in his body (possible encephalitis)? My child was healthy before all these shots…they made him sick. Oh, and the diarehhea, they gave him something that was supposed to “avoid diarreaha” well, it gave him it for months. They almost killed my child, with their GREED. It doesn’t work for many kids who have Immune dysfunction. What happened to the rest of their insides? Vaccines kill and hurt – but people don’t focus on that!!! Especially the fact that we are OVER vaccinating (See Holly’s Law NJ) NJ #1 in Shots/Pharma = #1 in Autism!

Again, having worked with adults with autism up to 85 years of age…the stories of regression taking place are still there. Just for different reasons. My son talked and developed just like his sibs until his dad was sent to Korea…my son stopped talking and started having tantrums when our dog died…my son stopped talking and playing when we moved. My brother-in-law has autism and regressed after his dog was hit by a car. The stories are just different now because children receive shots about the same time that brain begins using both hemispheres for language and social functions instead of one. (this can be checked by looking up the UCLA joint attention study)

Regression would tell us that something changed…read up on PKU…the child is slowly poisoned by an inability to process phenylalinine. It is a genetic disease. I can see correlations in regressive autism. We just haven’t figured out what.

Having said that, my son suffered an Hypotonic-Hyporesponsive episode, a “brain swelling” following the DTP at 2 months. I didn’t know it was a compensable NVICP injury.

God, how I wish we lived near Hopkins/etc. But, hey – at least the consortium folks at my location watched my baby – and truth be known, we have nothing to complain about – how amazingly lucky my younger child was followed from infancy. Sadly, that one is now one of the NTs-w/issues/gestation from hell children that they would like to follow until they are 25 – guess why? :(

So – Autism Speaks – how about pouring money into preventing schizophrenia? I told you I’d love to live near an earlistudy site. Oh but, let’s just forget any biomarkers/science/medicine and just give that one behavioral therapy too. I”m sure it’ll be very beneficial for schizophrenia :).

Just a note on your article about the CDC numbers and study. Although the increase in diagnosis of autism may be due to a broader definition that is accepted by the medical community as a whole…the CDC study uses strick DSM-IV criteria and looks through school records blindly to determine how many 8 year olds from a given year meet the criteria for autism, PDD,NOS or Aspergers. They do not have access to information about if the child already has a diagnosis. I worked for an agency involed in the original study where the numbers increased to 1:150. Therefore, increase awareness or diagnostic differences cannot explain the CDC numbers. It does explain the difference in CDC’s report and the numbers such as 1:90 that are reported by some groups based on how many cases are being diagnosed. Just feel it is important to understand how the numbers are being determined. CDC may of changed how they do the study since the release of the 1:150 numbers, but doubtful as it would skew the earlier research.

It is likely that a significant portion of autism diagnoses can be directly attributed to the expanding/evolving/enlightening nervous system. While symptoms of the expanding nervous system can feel profoundly disabling in our world — because those with expanded systems perceive the world from a profoundly expanded state of awareness (even if it doesn’t always seem like this to an observer) it is actually a significant step in our evolution. The adventure in an evolutionary brink/shift is recognizing what is occurring before we have the conscious capacity to understanding it. Those born with expanded nervous systems can become easily disoriented, unless they learn how to entrain their mind to the Light/Still Core within as a compass bearing. And when those who do not have an expanded nervous system (yet!), are trying to help, it creates a rather interesting circumstance. Brilliant minds are often attributed to being on the autistic spectrum, which is direct evidence for the expanded nervous system/extrasensory perception. There is profound evidence for this view of an expanded/awakening nervous system/mind, if one is willing to consider cosmology and quantum science – the science of wave-particle fields that comprise all of existence, including ourselves (we are not our bodies, we are consciousness/life temporarily housed within what we call bodies).

Important note: There are many circumstances in our world that may also causing symptoms that present on our human created “autism spectrum” that are not a result of the expanded nervous system (such as poisons in food, environment, products). We’re speaking here of the astonishing numbers of those presenting in our times that correlate perfectly with an expected and long predicted leap in our evolution. Individuals with autism are also causing us to slow down our fast paced lives in order to be able to assist them and tune into our own expanded states of awareness (in simple terms, tune into our heart’s wisdom which is wise and insightful, but such heart-based intelligence only works in the present moment). The circumstance of autism is causing those of us with less expanded states of awareness to slow down and go into our heart may also be part of what is assisting our collective leap in consciousness – we cannot feel God/the Unified Source Field unless we are listening for it from an expanded state.

I had a brother with autism diagnosed in 1968. (1-5 in 10,000) My mom was only 31 when she gave birth to him.
I have an ASD 15 year old son with many identical traits as his “Uncle Sam” (uncle Sam passed away at the age of 30 from choking on food)
I think in many cases genetics play a role.
I also think there is a herpes virus connection in many.
But who am I?
A 53 year old woman who is tired of no answers since she was a 7 year old girl!

I would like to know why AS is not supporting WPI’s research in trying to find out why 14 out of 17 ASD children tested positive for XMRV and finding treatments for this retrovirus. This retrovirus would explain the “heritabilty” of autism and why the numbers are increasing so dramatically. XMRV is also associated with ME/CFS and many people that I know that suffer from this have ASD children or ASD family members. There are many papers regarding the autoimmune dysfunction problems in ASD and I still do not know why we are going over and over this and not getting to the meat of the matter. Every day, there could be an XMRV mother (not knowing that she may have this retrovirus) and could transmit this virus via breast feeding to her healthy child. Vaccinations could also trigger this virus which would explain why more children are becoming sick with the increased vaccination schedule.

Hello! Many beings with highly sensitive/expanded nervous systems are part of humanity’s mind’s evolution/awakening to levels of awareness that are not accessible to many humans. From our limited perspective this seems profoundly disruptive to both those with autism, and those who are interacting with such beings. Ponder that we know we are more than our bodies. We have a consciousness or awareness. We can “think” and create and dream and bring our thoughts and dreams into form (the computer I type on began as “an idea”). Our consciousness/awareness/the spirit that inhabits our physical bodies has access to exceptional levels of awareness that we don’t presently perceive. Bring to mind all of humanity’s turned-off DNA. This DNA is starting to turn back on. Genes have been identified related to brain growth that are turning back on. Knowledge of an evolutionary leap for our mind circulates widely in many circles (bring to mind all the hype about 2012), but because we’re still learning how to integrate this expansion while we’re experiencing it first hand, from a scientific perspective, what is being suggested is considered “fringe,” like evolution was considered fringe in its day. Accepting new information that we don’t presently have the awareness to comprehend takes awhile, but people have existed in all eras of history that access higher states of awareness, it’s just never been on such a massive scale. This information is not offered to give false hope for any individual case. It is offered to suggest that as we slow down and listen within and observe the children, and interact with these beings by entering their world rather than trying so hard to make them conform to our far more limited level of awareness, we will discover remarkable information far beyond our present perception. Many of those with expanded nervous systems are not linear thinkers, which is why they may feel “unreachable” at times. They are multi-dimensional perceivers of states of awareness of Divine Intelligence.

While it is true that we are poisoning ourselves and our children by our own choice – not one of us has to purchase the products that we do – the reason for the astonishing increase in autism is the fact that our nervous system is expanding because our level of consciousness is expanding. The difficulty is that those who are making diagnosis that call this circumstance “a disability” are not looking in the right place. We need to enter the world of the children/adults with autism to realize that their consciousness is far more developed than our, only they cannot find a bearing in our world because we keep trying to “fix” and medicate them and ourselves. If we slow down – as many are doing – and listen with our hearts to these beings, giving them peace and telling them how awesome and beautiful and valuable they are to our world, we would find as a collective that this situation will begin to smooth out. Consciousness is LIGHT. It is intelligence far beyond our tiny huge human egos who think we have it all figured out and that something is broken. We need more of us willing to speak out to help these children find a compass bearing of Love within themselves (most know how to do this naturally) and for all of us to slow down and pay attention to what is really going on here. Trust the inward state of children. Affirm their beauty and stop thinking of this as a problem. Say yes to healthy foods and healthy thoughts and exercise and telling each other how beautiful we are, and simply don’t pay attention to what poisons us. The beautiful thing about a free market economy is that people will stop making what doesn’t sell. The choice to remember love or to forget love is up to us.

Here is an article called Honoring the Inward State of Children. It addresses the highly sensitive nervous system. Bright Blessings to all who are diligently working to bring peace to minds and hearts.

The 600% increase is an increase in subjective labels, not concrete evidence of drastic changes in environment, brain chemistry, spiritual perception, or whatever you people are claiming. There is no objective diagnosis for autism, and it’s become a fad to apply that label to any child with a possible developmental issue. When psychiatry stops being so ridiculously mutable with its diagnostic manuals, then you can start worrying about the epidemics it uncovers. Until then, turn to the field only as a last possible resort.

I have read somewhere about a possible link between the herpes simplex virus and autism.
This is frightening because the WHO estimates that 85% of the worlds population is infected with it and there is no cure for it.

As we continue to explore that the increasing incidence of our expanding nervous system (often called “autim”) is evidence of our biological evolution. This expanding nervous system sensitivity is leading to some strange manifestations in our physiology and behaviors. As we frame and realize autism is a gift and an evolutionary step forward, even if to us it seems at times like a limitation or a shift backwards, everyone will find creative ways to expand communication channels and courage to try to things and to not judge anyone (all folks are really doing their best always and we all have gifts to share). As we realize why it matters to always uplift and see all circumstances and people as beautiful and whole just as we are, all humanity will relax and find wondrous solutions, as so very many are doing, including Autism Speaks communities, that help us flow with shifting within our species. At the very least, the more we affirm and rest ourselves (our own minds and hearts) and encourage those with autism to know they are beautiful and whole with astonishing gifts to share with us all, miracles of healing hearts will resound. Share your stories. Thank you for creating such a wonderful tool for sharing. Laura Bedford